Electric meter.



No. 698,650. Patented Apr. 29, |902.

T. DUNCAN.

ELECTRIC METER.

(Application fixed Aug. 3:1899.) (No Model.) 2 Sheets-Sheet I.

'-N. 693,65. I Patented Apr.- 29, |902.

" A T.,nuNcAN.

ELECTRIC METER.

(Application led Aug'. 3, 1899.)

(No Model.)

2 Sheets-$heet 2.

flag. 3.' 3565@ if UNITED 'STATES PATENT omet. N

` 'rnoMAs DUNCAN, oncnIcAco, ILLINOIS, AssIGNoR To Tur; sinM'ENs aHALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS;

" Y ELECTRIC" METER.

SPECIFICATION fomingpat gf Leners recent Nq. ee 8,650, .mais` Aprn 2e,leoa. j u Appiicaiogfuea August3.1899'..-serinrmzaeva (Nomaden Y l A.

Be it known that I, THOMAS"DUNCAbLof,`

Chicago, in the county of Cook` and State of Illinois, have inventedcertainnew and useful Improvements in Electric Meters, (Case NmV 53,) ofwhich the following is aspecificatiomf vtive forcewhich it represents.

The invention `consists in the matters hereinafter described, andparticularly pointed out in the appendedclaims, and will befullyunderstood from the following detailed description of the constructionsillustrated in the accompanying drawings, in which- Figures l and 2 arepartially diagrammatic plan views of meters embodying my invention. Fig.3 is a similar front elevation of still another meter Vconstructionembodying my invention, but modified somewhat from either formpreviously shown. Figs. 4, 5, and 6 are vector diagrams of the essentialcurrent eects.

As shown in Fig. l, A designates the rotary armature of the meter, B andC the series and volt field-coils, and D an impedancecoil connected inseries with the volt fieldcoil C in a shunt-circuit between the mainleads w and w of the work-circuit. D' is a secondary impedance-coilplaced in inductive relation to the coil D and connected in a secondshunt-circuit, in which the volt field-coil C is also connected inseries. The terminals d and d of the two coils D and D are shown asconnected to the leads w and w, respectively, of the Work-circuit, whiletheir opposite terminals d2 and d3 are connected,through theyolteld-coil C, with the leads fw' and w, respectively. Adjustableresistances r and r' are shown as inserted in the terminals d' and d3 toassist in the adjustment and calibration of the meter, and as a furtherimprovement a starting-coil D2 is shown as inserted in the secondaryshunt-circuit between the coils C and D to assist in overcoming thefriction and inertia of the meter, especially under light working loads.The construction` shown in `2 is similar, except that the secondary coilD, instead of being Wound upon the same magnetic core D3 with the p`ri`marycoil D, is wound upona separable armature D4, `which for purposes of"fu rther a'djustment maybe Separatedfrom the main `core D3 by spaceblocks s n,ofauy desired thickness. This is also true of theconstruction shown in Fig. An additional adjustable resistance r2 isalso shown in Fig. as inserted in `the terminal d2 ot `the primaryshunt-circuit, while in Fig. 3 only the single adjustable resistance o"in the terminal d3 of Vthe secondary shuntfcircuit is provided. The

friction-coil D2 is not shown in Fig. 3, but can be supplied in anysuitable manner. In all of said views, G indicates thealternatingcurrent generator, andL and M the lamps and motorsconstituting the load.

Any suitable mechanism R may beeinployed to register the revolutions ofthe ar mature, and a magnetic drag Smay be applied in the usual mannerto maintain the number of revolutions proportional to the torqueexerted, such devices being indicated in Fig. 3,'but omitted fromtheother views of the drawings for the sake `ot simplicity ofillustration. These features', however, constitute in themselves no partof the present improvements and are mentionedmerely for the purpose ofenabling the complete installation to be clearly understood.

The essential phase relations resulting in the present improvement areshown graphically in Figs. 4, v5, and 6, in which the line E representsthe impressed electromotive force ot the work-circuit, and F the primaryshunt-current, which will naturally be lagged somewhat less than ninetydegrees behind the electromotive force E by the impedancecoil D, Fig.4.The secondary impedance-coil D will act as a primary on the coil I) andinduces a secondary current F in the primary shunt-circuit, so that thetotal eective current through this circuit is the resultant f, obtainedby completing the parallelogra'mon lines F and F', Fig. 5. This maystilllag less than ninety degrees; but" the total current supplied to thevolt field-coil C includes not only such resultant, but the secondaryshunt IOS 'tion-circuit.

current F2 through the coil D7, the et'tect of whichis to produce aiinal resultant F3, which Y by suitable adjustment, as by means ot'eitherv or all of the adjustable resistances fr, r', 'and r2, may begiven the exact ninety-degree lag desired.- "4

AIn the preferred embodiment ot' the invention, as illustrated, thepressure-winding is subdivided into two coils, the coils having a commonterminal, which is connected with one side ot the distribution-circuitthrough' an impedance-coil, the remaining terminal of one of theremaining pressure-coils being connected with the other side of thedistribution-circuit through a second im pedance-coil,"

'the impedance-coils being preferablyinductively related, while theremaining terminal of thel remaining.pressure-coil isalso connected withthe latter Lside of the distribu- I claim as my invention- 1. Anelectric meter provided with an armature, a series coil connected inseries in the work-circuit, a volt-coil connected in two shnnt-circuitsbetween the main leads of the work-circuit, and impedance-coils insertedin each of said shunt-circuits, substantially as described.

2. An electric meter provided with an armature, a series field-coilconnected in series -in the Work-circuit, a volt field-coil connected intwo shunt-circuits betweenv the main leads of theworlc-circuit, andimpedancecoils inserted in each of said shunt-circuits `and arranged ininductive relation to each other, substantially as described.

3. An electric meter provided with an armature, a series field-coilconnected in series in the work-circuit, a volt field-coil connected intwo shunt-circuits between the main lead of the work-circuit,impedance-coils inserted in each of said shunt-circuits, and a nal ofthe remaining pressunefcoil isalso connected with thelatter side of thedistributioncircuit, substantially as described.

5. In a meter, the combination with current and'pressu're windings, thepressure-windings being subdivided into two coils having a com- 'monterminal, an impedance-coil connecting the said common terminal ywithoner side of a distribntionfcircuit, a second impedance-coil kconnectingthe remaining terminal of a pressure-coil with the other side ot' thedistribution-circuit while the remaining terminal ot' the remainingpressure-coil is also connected with the latter side of thedistribution-circuit, and'a Vphase-modifying device r connected in shuntofthe distribution-mains,sub stantially as described.

7. In a meter, the combination with current and pressure windings, thepressure-windings being subdivided into two coils having a commonterminal, an impedance-coil connecting the said common terminal with oneside of a distribution-circuit, a second impedance-coil connecting theremaining terminal of a pressure-coil with the other `side of thedistribution-circuit while the remaining terminal of the remainingpressure-coil is also connected with Athe latter side of thedistribution-circuit, the impedance-coils being inductively related, anda phase-modifying device r' connectedin shunt of thedistributionmains,sub stantially as described.

In testimony that I claim the foregoing as my invention I affix mysignature, in presence of two subscribing witnesses, this 25th day ofJuly, A. D. 1899.

THOMAS DUNCAN. W'itnesses:

ALBERT H. GRAVES, HENRY W. CARTER.

IOO

